This might be related to bug 1324529. On my Lenovo T530, there is only thinkpad_screen in /sys/class/backlight. The fixes suggested here (the acpi_backlight=vendor and 80-backlight.conf) do not fix the issue for me and echoing numbers into /sys/class/backlight/thinkpad_screen/brightness does nothing.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1307064 Title: Ubuntu 14.04 Beta cannot adjust brightness on Lenovo Ideapad Z570 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1307064/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs